package cn.com.scitc.servlet;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadBase;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Iterator;
import java.util.List;

@WebServlet(urlPatterns = "/uploadProcessServlet")
public class UploadProcessServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        System.out.println("/uploadProcessServlet post");


        final long MAX_SIZE = 300 * 1024 * 1024;// 设置上传文件最大值
        // 允许上传的文件格式的列表
        final String[] allowedExt = new String[] { "jpg", "jpeg", "gif", "txt", "png",
                "doc", "mp3", "wma", "m4a", "rar", "zip" };
        response.setContentType("text/html");
        // 设置字符编码为UTF-8, 统一编码，处理出现乱码问题
        response.setCharacterEncoding("UTF-8");

        // 实例化一个硬盘文件工厂,用来配置上传组件ServletFileUpload
        DiskFileItemFactory dfif = new DiskFileItemFactory();

        dfif.setSizeThreshold(4096);// 设置上传文件时用于临时存放文件的内存大小,这里是4K.多于的部分将临时存在硬盘

        String uploadDir = request.getServletContext().getRealPath("/ImagesUploadTemp");
        System.out.println(uploadDir);
        //dfif.setRepository(new File(uploadDir));// 设置存放临时文件的目录,web根目录下的ImagesUploadTemp目录

        // 用以上工厂实例化上传组件
        ServletFileUpload sfu = new ServletFileUpload(dfif);
        // 设置最大上传大小
        sfu.setSizeMax(MAX_SIZE);

        PrintWriter out = response.getWriter();
        // 从request得到所有上传域的列表
        List fileList = null;
        try {
            fileList = sfu.parseRequest(request);
        } catch (FileUploadException e) {// 处理文件尺寸过大异常
            if (e instanceof FileUploadBase.SizeLimitExceededException) {
                out.println("文件尺寸超过规定大小:" + MAX_SIZE + "字节<p />");
                out
                        .println("<a href=\"upload2.jsp\" target=\"_top\">返回</a>");
                return;
            }
            e.printStackTrace();
        }
        // 没有文件上传
        if (fileList == null || fileList.size() == 0) {
            out.println("请选择上传文件<p />");
            out.println("<a href=\"upload2.jsp\" target=\"_top\">返回</a>");
            return;
        }
        // 得到所有上传的文件
        Iterator fileItr = fileList.iterator();
        // 循环处理所有文件
        while (fileItr.hasNext()) {
            FileItem fileItem = null;
            String path = null;
            long size = 0;
            // 得到当前文件
            fileItem = (FileItem) fileItr.next();
            // 忽略简单form字段而不是上传域的文件域(<input type="text" />等)
            if (fileItem == null || fileItem.isFormField()) {
                continue;
            }
            // 得到文件的完整路径
            path = fileItem.getName();
            System.out.println("原始文件名：" + path);

            // 得到文件的大小
            size = fileItem.getSize();
            if ("".equals(path) || size == 0) {
                continue;
            }

            // 得到去除路径的文件名
            String t_name = path.substring(path.lastIndexOf("\\") + 1);
            System.out.println(t_name);
            // 得到文件的扩展名(无扩展名时将得到全名)
            String t_ext = t_name.substring(t_name.lastIndexOf(".") + 1);
            // 拒绝接受规定文件格式之外的文件类型
            int allowFlag = 0;
            int allowedExtCount = allowedExt.length;
            for (; allowFlag < allowedExtCount; allowFlag++) {
                if (allowedExt[allowFlag].equals(t_ext))
                    break;
            }
            if (allowFlag == allowedExtCount) {
                out.println("请上传以下类型的文件<p />");
                for (allowFlag = 0; allowFlag < allowedExtCount; allowFlag++)
                    out.println("*." + allowedExt[allowFlag] + "   ");
                out
                        .println("<p /><a href=\"upload2.jsp\" target=\"_top\">返回</a>");
                return;
            }

            long now = System.currentTimeMillis();
            // 根据系统时间生成上传后保存的文件名
            String prefix = String.valueOf(now);
            // 保存的最终文件完整路径,保存在web根目录下的ImagesUploaded目录下
            String u_name = uploadDir + "/" + prefix + "." + t_ext;
            //String filename = prefix + "." + t_ext;
            //根据原文件名保存文件
            String filename = t_name;
            try {
                fileItem.write(new File(u_name));
                System.out.println(filename);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
}
